Eraser holder



Sept. 13, 1938. A. s. DYSART 2,129,831

ERASER HOLDER Filed May 13, 1957 E IN V EN TOR.

W/ ATToRN Y Patented Sept. 13, 1938 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates primarily to mechanical pencils and more particularly to an eraser therefor.

An object of the present invention is to improve the veraser construction of a mechanical or other pencil enabling an elongated eraser to be used and successively advanced axially as it becomes worn.

One feature which enables me to accomplish the above named object is that a threaded member is mounted within the casing of the pencil and in engagement with the periphery of the eraser, there being means to rotate the eraser to cause axial movement of the eraser in either direction relative to the casing.

Another feature of importance is that an enclosing cap may be provided for the eraser extending over the end of the pencil casing, the cap being adapted to engage the eraser and provide means for rotating it relative to the casing.

With these and other objects in View the invention may include the features of construction and operation set forth in the following specification and illustrated in the accompanying drawing.

This application is a continuation in part of my copending application Serial No. 65,600, led February 25, 1936.

In the accompanying drawing annexed hereto and forming a part of this specication, I have shown the invention embodied in a conventional form of mechanical pencil of the magazine type, but it will be understood that the invention can be otherwise embodied and that the drawing is not to be construed as dening or limiting the scope of the invention, the claims appended to this specication being relied upon for that purpose.

In the drawing:

Figure 1 is an outside longitudinal View of a mechanical pencil having the p-resent invention applied thereto, a part being broken away to more clearly show the construction.

Fig. 2 is a fragmentary longitudinal section upon a larger scale and showing one preferred form of the invention.

Fig. 3 is a cross-sectional View taken on the plane of line 3 3 of Fig. 2.

Fig. 4 is a View similar to Fig. 2.and showing r a modified form of the invention.

"o Fig. 5 is a side elevation partly broken away of the cap member shown in Fig. 4.

Fig. 6 is an end View of the cap member shown in Fig. 4.

Fig. '7 is a longitudinal sectional 55 View of an (Cl. 1Z0-36) eraser having feeding means provided within a central axial hole therethrough; and

Fig. 8 is a longitudinal sectional View of a pencil eraser having positive advancing means forming a xed part of the pencil structure.

In the above mentioned drawing there have been shown several embodiments of the invention which are now deemed preferable, but it is to be understood that changes and modiiications may be made within the scope of the appended claims Without departing from the spirit of the invention.

Brieily, and in its preferred aspect, the invention may include the following principal parts: First, a casing; secon-d, an eraser of elongated form threaded within one end of the casing; and third, a member adapted to engage the eraser so that it may be rotated and thereby be advanced axially in either direction.

Referring more in detail to the figures of the drawing, and first to Figs. 1, 2 and 3, I provide a casing I0 of usual form found in mechanical pencils with an elongated eraser II. The eraser II shown most clearly in Fig. 2 of the drawing is polygonal in cross section and engages a member I2 secured within the casing I0. The member I2 has a helical projection adapted to engage and cut slightly into the eraser II at its corners. By rotating the eraser II it will be advanced axially in either direction depending upon its direction of rotation. Preferably and as shown in Fig. 2, the member I2 comprises a helically coiled strip one longitudinal edge of which is bent inwardly to form a helically extending projection having two or three convolutions. The edge of this projection is sharp enough to cut into the outer surface of the eraser I I and thus cause it to advance when rotated. As the eraser II is preferably hexagonal or octagonal the edge of member I2 engages the eraser more deeply at its corners than upon the sides.

To rotate the eraser II and also to enclose it when not in use there may be provided a cap member I3 tting tightly over the end of the eraser and on to the end of the casing I0. In the form of cap member I3 shown in Fig. 2, there is formed a polygonal portion I4 closely fitting the outside surface of the eraser. By rotating the cap member I3 While in position on the casing I0 the eraser I I may be advanced as much as required when it becomes worn away and requires replacement.

In Figs. 4, 5 and 6 there is provided the feeding member I2 within a casing I0 similar to corresponding parts shown in Fig. 2. The eraser I5,

however, is modied materially by being cyline drical in form and having a non-circular central longitudinal hole II. The cap member I6 shown in this gure is provided with a central elongated projection I8 permanently secured within and extending centrally within the member I6. This projection I8 in cross section corresponds to and is adapted to fit Within the opening I'I Within eraser I5.

The cap members I3 and I6 are retained in position on their erasers by contact with the surfaces of the erasers I I and I5 respectively and also serve as rotating means therefor by the engaging surfaces of the cap members and erasers being non-circular.

In Fig. 8 another embodiment of the invention is shown, this form having no cap member but being provided with positive and permanently mounted feeding or advancing means within the casing for the eraser I9. A casing IIJ is provided with a central threaded member 20 preferably and as shown secured to a transversely disposed disk 2l secured within the casing I0 at an intermediate point. At its inner end the eraser I9 is provided with a nut 22 threaded upon screw 20 and preferably moulded or imbedded within the eraser I9. Also the eraser I9 is provided with a central hole extending axially from end to end and of sucient diameter to permit the screw 2li to freely enter.

To rotate the eraser IS there may be rotatably mounted within the end of casing f an annular member or sleeve 23. The outer end of this sleeve 23 may be enlarged to form a ange 2d the outer surface of which may be roughened or knurled to aid in rotating it. The inner surface of the sleeve 23 lightly engages the surface of eraser I9 so that rotation of the sleeve 23 will also rotate the eraser I9.

The embodiment shown in Fig. 7 employs an eraser 25 having a central smooth hole 26 extending throughout its length. Secured within the casing and preferably to a disk 21 therein is a rod 23 fitting easily within the hole 26. At the free end of rod 28 is a head portion 29, the peripheral portion of which is helical and of such diameter that it will cut or force its peripheral edge into the eraser. By rotating the eraser it will be advanced due to this helical contact between the eraser and head. As shown in this gure, the disk 21 may have a hole 30 therethrough. This may be provided so that in mechanical pencils of the magazine type lengths of lead may be supplied to the magazine directly through the disk.

The member I2 and head portion 29 have been described as being sufficiently sharp to cut into the material of the erasers I5 and 25. If desired, however, the erasers, previously to assembling, may be provided with the necessary helical groove portions on the outside polygonal surface as in Fig. 2 or along the surface of hole 26 as in Fig. '7. These grooves would be cut by any appropriate means and in the edges of member VI2 or head 29 would not be required to be sharp enough to cut into the erasers but would engage Within the grooves previously cut therein.

I claim as my invention:

1. An eraser holder comprising in combination, a casing having a screw threaded portion therein, an eraser extending within an end thereof and engaging said screw threaded portion, a cap fitting over the end of said casing and eraser, and

means on said cap engaging said eraser, whereby said eraser may be advanced along said screw threaded portion.

2. An eraser holder comprising incombination, a casing having a screw threaded portion therein, an eraser having a polygonal cross section extending within an end thereof and engaging said screw threaded portion, a cap fitting over the end of said casing and eraser, and means on said cap engaging the polygonal cross section of said eraser, whereby said eraser may be advanced along said screw threaded portion.

3. An eraser holder comprising in combination, a cylindrical casing, an eraser extending within one end thereof, an axially extending threaded member mounted centrally within said casing and retained against rotation, said eraser having a central hole extending therethrough, and a nut embedded in said eraser engaging said threaded member.

4. An eraser holder comprising in combination, a cylindrical casing, an eraser extending within one end thereof, an axially extending threaded member mounted centrally within said casing and retained against rotation, said eraser having a central hole extending therethrough, a nut embedded in said eraser engaging said threaded member, and a cap fitting over the end of said casing and eraser and engaging a non-circular surface thereof, whereby said eraser may be advanced along said threaded member.

ARTI-IU R S. DYSART. 

